CSI finale will feature a 'pivotal death'; find out which original character will return in two-hour episode

The original CSI series is coming to an end after 15 years as the two-hour series finale is slated to air on 27 September.

According to a report, the finale will feature a major character's death as CBS is bringing back original stars William Petersen (Gil Grissom) and Marg Helgenberger (Catherine Willows) to work on a final case together.

TVLine reports that the show's "Two-hour September 27 swan song will kick off with a significant time jump — we're talking roughly six months. I'm also hearing there's a pivotal death."

The season 15 finale saw Nick Stokes (George Eads) leaving his post in the Las Vegas Crime Lab to become the department chief in San Diego. He was the last original cast member to exit the show.

The two characters who will not be in the final episode are - Elisabeth Shue, who played Julie Finlay, and George Eads, aka Nick Stokes.

It is unclear how the producers will deal with Shue's absence. Eads has opted not to participate, according to TVLine.

Melinda Clarke will also appear in the big finale, reprising the role of Lady Heather.

CSI creator Anthony Zuiker dished on what to expect from the two-hour episode.

Zuiker told Adweek, "It is a love letter to the fans. It's a complicated and rich case that brings all of our people back together, and has a very satisfactory conclusion that life will go on. And there's many, many takeaways that I think our audience will appreciate. If you are a devoted fan, you'll be very, very pleased emotionally how things wrap up. And if you're a new fan, I think you'll find yourself in for a two-hour ride."

The iconic series has already led to three spinoffs, and not all the characters are going away. Supervisor D B Russell, played by Danson, will move to CSI: Cyber, where he will team up with Academy Award-winner Patricia Arquette.